/* @(#)s_rint.c 5.1 93/09/24 */
/*
 * ====================================================
 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
 *
 * Developed at SunPro, a Sun Microsystems, Inc. business.
 * Permission to use, copy, modify, and distribute this
 * software is freely granted, provided that this notice
 * is preserved.
 * ====================================================
 */


#include "float.h"
#include "math.h"

static const double
TWO52[2]={
  4.50359962737049600000e+15, /* 0x43300000, 0x00000000 */
 -4.50359962737049600000e+15, /* 0xC3300000, 0x00000000 */
};

double
rint(double x)
{
    int i0,j0,sx; /*lint !e578*/
    unsigned int i,i1;
    double w,t;
    EXTRACT_WORDS(i0,i1,x);
    sx = (i0>>31)&1;
    j0 = ((i0>>20)&0x7ff)-0x3ff;
    if(j0<20) {
        if(j0<0) {
        if(((i0&0x7fffffff)|i1)==0) return x;
        i1 |= (i0&0x0fffff);
        i0 &= 0xfffe0000;
        i0 |= ((i1|-i1)>>12)&0x80000; /*lint !e501*/
        SET_HIGH_WORD(x,i0);
            STRICT_ASSIGN(double,w,TWO52[sx]+x);
            t =  w-TWO52[sx];
        GET_HIGH_WORD(i0,t);
        SET_HIGH_WORD(t,(i0&0x7fffffff)|(sx<<31));
            return t;
        } else {
        i = (0x000fffff)>>j0;
        if(((i0&i)|i1)==0) return x; /* x is integral */
        i>>=1;
        if(((i0&i)|i1)!=0) {
            /*
             * Some bit is set after the 0.5 bit.  To avoid the
             * possibility of errors from double rounding in
             * w = TWO52[sx]+x, adjust the 0.25 bit to a lower
             * guard bit.  We do this for all j0<=51.  The
             * adjustment is trickiest for j0==18 and j0==19
             * since then it spans the word boundary.
             */
            if(j0==19) i1 = 0x40000000; else
            if(j0==18) i1 = 0x80000000; else
            i0 = (i0&(~i))|((0x20000)>>j0);
        }
        }
    } else if (j0>51) {
        if(j0==0x400) return x+x;    /* inf or NaN */
        else return x;        /* x is integral */
    } else {
        i = ((unsigned int)(0xffffffff))>>(j0-20);
        if((i1&i)==0) return x;    /* x is integral */
        i>>=1;
        if((i1&i)!=0) i1 = (i1&(~i))|((0x40000000)>>(j0-20));
    }
    INSERT_WORDS(x,i0,i1);
    STRICT_ASSIGN(double,w,TWO52[sx]+x);
    return w-TWO52[sx];
}

/*added by 10.15 */
long long llrint(double x)
{
    return (long long)rint(x);
}
